1. Field of the Invention
This invention relates to a system and method for monitoring activity of an animal. In particular, the invention relates to a method for monitoring activity of an animal in a system for housing freely moving (free walking) animals comprising a plurality of animal ID stations, the method comprising the steps of a) recording a first visit of said animal at a first of said animal ID stations, and b) recording a subsequent second visit of said animal at a second of said animal ID stations.
2. Description of the Related Art
Known methods of monitoring activity of freely moving animals generally include an animal identification means. However, it is most often used in the milking context to simply record the times of milking, without drawing any conclusion about the activity of the animal. Still, in e.g. dairy and pig farming it is desired to be able to automatically monitor the activity of animals in order to determine if an animal behaves outside of the generally normal behaviour. Such atypical behaviour can be a sign that the animal is in heat, or that it is ill or the like.
For example, in GB 2,076,259, in order to detect heat in cows it is described to equip the cows with a so-called activity meter attached to one of the cow's legs. A cow in heat will be more active and walk more. The activity meter can register this. In order to automatically alert the farmer the activity meter can upload the information continuously or batch wise to a computer. This type of system is prone to give false positive readings because the movements of the legs do not always indicate that a cow is actually walking
In FR2759541 an animal activity monitoring system is described in which cows are continuously monitored with the aid of a surveillance camera and a visual identification marker on the animal. The positions of the cows are recorded and stored in a memory. These data are used to calculate the amount (d) a cow has displaced itself over a period of time. The amounts (d) are continuously determined for all cows of the herd and are sent to an alerting means to inform the farmer which cows of his herd are in heat. A drawback of this system is that is depends on an extensive video surveillance system that is expensive. Moreover, in most dairy stall layouts, there are too many parts for such a system to cover, such as milking stalls, feeding stations and so on. Furthermore, it is not clear what happens when vision is blocked by e.g. a cow standing in front of a lying cow or disappears around a corner.
In EP0624313 an animal activity monitoring system is described that will equip the animal with an identification means, such as tag, that communicates with an antenna or transceiver. The antennae transceiver devices are distributed in a stable, for example at a milk stand, a feeding station or the like. The transceiver device can recognize the signal received from a tag of a cow and register when, how long and where a cow is. On the basis of these data visiting frequency distribution, displacement patterns etc can be determined and if so desired reproduced. In particular in EP0624313 it is proposed to calculate the number of visits per day of an animal to a specific station, or a frequency distribution of the number of visits over a number of days, and the like. Still it appears that this system is not always best suited to provide the most reliable information about activity of the animal.